The urgently organized trip, which has been confirmed by committee staff and a senior US official, is the latest twist in the saga of Davis, who killed two Pakistani men on January 27, allegedly in self-defence.

Senator Kerry’s mission is not trying to secure Davis’ release, but to “help tone down the rhetoric and reaffirm the US partnership with Pakistan,’ The Boston Globe quoted the US official, as saying.

Despite the US insisting that Pakistan should free Davis as he is entitled to “full immunity from criminal prosecution by Pakistan” under the Vienna Convention on Diplomatic Relations of 1961, he was remanded in judicial custody for 14 days on Friday, with the next hearing due on February 25.

The Davis detention issue seems to be taking its toll on US-Pak relations, which were already strained over stepped-up drone strikes in Pakistan’s militant-infested tribal region and disagreements over the war in neighbouring Afghanistan.

A senior Pakistani official, speaking on the condition of anonymity because of the sensitivity of the issue, said that Kerry, who left for Pakistan on Monday night, would travel first to Lahore to speak to local officials who arrested Davis, and then to Islamabad, where he would talk to senior officials of the federal government.

“The idea is to try to bring both countries back from inflammatory rhetoric,’ the official said, adding, “Kerry is a man with very high credibility in Pakistan.’

Senator Kerry has developed closed relations with Pakistan leaders over the years and pushed through a 7.5-billion-dollar, five-year aid package for the country, the report said. He has travelled to Pakistan four times since he became Chairman of the powerful Foreign Relations Committee in early 2009.

The Obama administration has sent Kerry on delicate foreign policy missions in the past as well, the report said. In 2009, Kerry was sent to try to persuade Afghan President Hamid Karzai to accept an international election commission’s vote count after a bitter presidential election. Last fall, he delivered messages to Sudanese leaders in the run-up to a tense referendum on independence for the south. (ANI)